Patent specification U.S. Pat. No. 7,543,896 B2 discloses, for example, a hydraulically controlled storage chamber valve in which a spring-prestressed ball-type seat valve is opened via a tappet in the storage piston. This takes place at a system-specified force ratio between the spring prestressing force and hydraulically active force. The actuation of the ball-type seat valve takes place via a cylindrical metallic tappet which is pressed into the storage piston. The storage piston also receives a sealing ring and a guide ring. An appropriately prestressed compression spring is located between the storage piston and the closing cover which is connected to the pump housing by holding calking. The spring force acts counter to the hydraulically active force at the storage piston and, when there is an excess of spring force, causes displacement of the storage piston/tappet combination in the opening direction of the storage chamber valve. In this case, the ball is moved out of the seat by the tappet and the storage chamber valve is opened.
Laid-open publication DE 42 02 388 A1 describes, for example, a hydraulic brake system for a motor vehicle. The brake system described comprises a hydraulically controlled storage chamber valve, with a closing element which is prestressed via a first compression spring and seals off a valve seat in a valve body, and with a tappet which is connected to a storage piston loaded by a second compression spring and presses the closing element out of the valve seat when a specified force ratio prevails between the spring prestressing forces and a hydraulically active force. In these designs of storage chamber valves, the sealing body of the valve closed with spring assistance is moved by a pin connected to the storage piston into the open position as soon as the storage chamber volume undershoots a threshold value, that is to say the storage piston approaches the stop.